The LiftMaster CPS3-N4 NEMA 4 Option Card with Photo Eyes (Dual Set) is a factory accessory kit for compatible LiftMaster commercial and industrial door operators that need monitored entrapment protection in demanding environments. The included option card interfaces with the operator’s control logic to enable a supervised safety circuit, while the dual photo eye set establishes an infrared safety beam across the opening to stop or reverse the door when the beam is interrupted during closing. Built to a NEMA 4 rating, the components are engineered for wet, dusty, or washdown-prone locations, making this an ideal replacement part or upgrade for exterior doors, car washes, agricultural buildings, warehouses, and other harsh-use applications.
Designed for use with LiftMaster operators that accept the CPS3-N4 option, this monitored photoelectric solution helps support UL 325 safety requirements by detecting faults such as misalignment, wiring issues, or device damage and signaling the operator accordingly. Installation involves mounting and aligning the paired photo eyes at the proper height on each side of the doorway, wiring the sensors to the option card and operator accessory terminals, and configuring the operator to recognize the monitored device per the manufacturer’s instructions. For reliability and compliance in commercial or industrial settings, LiftMaster recommends installation and testing by a qualified door professional. Keywords: LiftMaster CPS3-N4, NEMA 4 photo eyes, monitored entrapment protection, commercial door operator accessory, industrial overhead door safety, replacement part, retrofit, UL 325.